A CDN, or Content Delivery Network, is a geographically distributed network of servers that cache and serve a website's static assets — images, scripts, stylesheets, fonts, video — from a location close to each visitor, instead of every request travelling back to a single origin server.
Definition
A CDN, or Content Delivery Network, is a geographically distributed network of servers that cache and serve a website's static assets — images, scripts, stylesheets, fonts, video — from a location close to each visitor, instead of every request travelling back to a single origin server. When a user in one region loads a page, the CDN's nearest edge node answers, cutting the round-trip distance and therefore the load time.
Beyond speed, a CDN absorbs traffic spikes that would overwhelm the origin, provides a layer of protection against denial-of-service attacks by soaking up volumetric traffic at the edge, and typically terminates TLS and applies caching, compression and image optimisation. For any site with an international audience, a CDN is close to mandatory: without one, visitors far from the origin experience slow pages regardless of how well the site is built.
In context
For iGaming affiliate sites, a CDN matters for both SEO and conversion. Page speed is a ranking and user-experience factor, and affiliate comparison pages tend to be image-heavy (logos, screenshots, badges), so serving those assets from the edge with modern formats and compression has a measurable effect on Core Web Vitals and bounce.
For sites targeting several countries from one domain, the CDN is what makes the experience acceptable in every GEO rather than only near the host.
There are operational caveats. Aggressive edge caching can serve stale content after an update, so cache-purge on deploy must be wired up.
Cache rules keyed on query strings interact with tracking parameters — a misconfigured rule can either cache per-unique-URL (defeating the cache) or strip parameters needed downstream. And a CDN that serves the HTML document itself, not just assets, needs its caching and its handling of bot traffic checked carefully so that search crawlers and tracking still behave as intended.
Worked example
An affiliate site serving one .com domain to users across Europe, Latin America and Asia adds a CDN. Largest Contentful Paint in the furthest regions drops from around 4.5s to 1.8s, the site clears Core Web Vitals thresholds it had been failing, and organic sessions from the distant GEOs rise over the following two months.
Related terms
Frequently asked questions
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